JPH1036336A - N-(2-naphthylsulfonyl)-n'-phenylurea and color developer for reversible heat-sensitive recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new compound which can form a color-developed image on a white background, causes color development and decoloration with only difference in the heating condition, has a high color contrast and excellent image preservability. SOLUTION: This compound is represented by formula I (X is -NHCO-, -NHCOO-, -NHCOS-; n is 15-20), typically N-(2-naphthylsulfonyl)-N'-[4-(n- octadecanoylamino)phenyl]urea. The compound of formula I is prepared from the reaction of a compound of formula II (n is 16, 18, 20) with a compound of formula III.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel N- (2-
The present invention relates to a (naphthylsulfonyl) -N'-phenylurea compound and a developer containing the same for reversible thermosensitive recording. N- (2-naphthylsulfonyl)-of the present invention
N′-phenylurea-based compounds include —NHCO— bonded to an N′-phenyl group; —NHCOO— or —NHCO
S intermediate group and — (CH ₂ ) _n —CH ₃ (n = 15 to ₂ )
0) those having a terminal group, these compounds
It is useful as a developer for reversible thermosensitive recording.

That is, the N- (2-naphthylsulfonyl) -N'-phenylurea compound of the present invention is used to reversibly develop and decolor a heat-sensitive recording dye by heating it. And the color development state and the decoloration state of the dye can be stably maintained at room temperature. Therefore, by using the compound of the present invention in combination with a color-developing / erasable dye precursor, for example, a leuco dye, as a developer for thermal recording, the contrast between the color hue of the dye and the decoloring hue is obtained. And a reversible thermosensitive recording medium having a high reversibility can be obtained. The reversible thermosensitive recording medium thus obtained can be used as, for example, prepaid cards, point cards, facsimile paper that is used many times, or a display material that does not require energy to hold an image.

[0003]

2. Description of the Related Art Conventionally, a thermosensitive recording medium has a compact recording device, is inexpensive, and is easy to maintain.
Computer, measuring equipment, cash register, CD / AT
It has been used as output paper for M, facsimile, automatic ticket vending machines, handy terminals and the like, and more recently has been used as a magnetic thermal card such as a prepaid card and a point card due to its combination with magnetic recording. In these conventional magnetic thermal cards, magnetic information can be rewritten each time it is used, but thermal recording images cannot be rewritten, so new information such as residual count is added to the part where no image is recorded. There must be. However, since the partial area where additional recording is possible is limited, it is unavoidable to reduce the amount of information to be thermally recorded,
The fact is that the card is recreated when the additional recording area is exhausted. As a means for solving such a problem, there is a strong demand for the development of a reversible thermosensitive recording medium capable of rewriting recorded information any number of times.

[0004] Against the background of garbage problems and deforestation problems that have been actively discussed in recent years, there is a demand for the recycling of thermal recording paper. There are various methods for regenerating thermosensitive recording paper. Among them, as a versatile method that does not require a large device such as a deinking device, the development of a reversible thermosensitive recording material that can be rewritten many times is Is desired.
Further, a reversible thermosensitive recording medium is disclosed in JP-A-3-233490.
As a recording material for a simple display as disclosed in Japanese Patent Application Laid-Open No. 5-42762 and Japanese Patent Application Laid-Open No. 5-42762. Development of a reversible thermosensitive recording material suitable for these apparatuses is strongly desired. .

[0005] Against these backgrounds, various reversible thermosensitive recording media have been proposed. For example, JP-A-63-107
JP-A-584, JP-A-4-78573 and JP-A-4-35878 disclose a polymer type reversible thermosensitive recording medium utilizing a change in transparency due to heating conditions. However, since this is a recording system utilizing transparency-white turbidity due to a phase change of a polymer, sufficient transparency or sufficient opacity cannot be easily obtained, and the contrast between a color-developed portion and a decolored portion is low. However, there is a problem that visibility in a dark place is poor. In addition, in general, a white image is recorded on a colored background, and it is difficult to obtain a so-called paper-like recording medium that records a colored image on a white background.

As a method for solving these problems, there has been proposed a dye-type reversible thermosensitive recording medium which enables reversible recording while using a dye used in a conventional thermosensitive recording medium. Such a dye-type reversible thermosensitive recording medium can easily record a color image on a white background,
In addition, since the recording method is a recording method utilizing a change in absorption wavelength due to heating conditions, a relatively high contrast can be obtained between a recorded image and an erased image. As such a dye type reversible thermosensitive recording medium, for example, the following method is known.

JP-A-58-191190 and JP-A-60-193691 disclose methods using gallic acid and phloroglucinol as color developers. However, since the use of water or water vapor is required for erasing an image, there is a disadvantage that the color erasing device becomes large. JP-A-60-264285 and JP-A-62-140881 disclose thermochromic materials having hysteresis. But,
Since the image holding temperature range of the image obtained by the thermochromic material is limited at both the upper limit and the lower limit, there are disadvantages that the apparatus becomes complicated and the operating temperature is limited. . JP-A-63-173
No. 684 discloses a method using an ascorbic acid derivative as a color developer. However, in this case, there is a disadvantage that the image cannot be sufficiently erased.

JP-A-2-188293 and JP-A-2-188294 disclose a method in which a salt of a specific organic acid such as gallic acid and a higher aliphatic amine is used as a color developer. . However, since the coloring reaction and the decoloring reaction are competing reactions, it is difficult to control so that either reaction proceeds selectively, and it is difficult to obtain a high contrast between the recorded image and the erased image. There is a disadvantage that. JP-A-5-124360 and JP-A-6-210954 disclose a method using an organic phosphoric acid compound having a long-chain alkyl group or a phenolic compound as a color developer. However, when erasing, there are drawbacks that the color may not be sufficiently erased, and the storability of the color image may be insufficient.

As described above, a number of techniques have been disclosed for reversible thermosensitive recording media, but each of them has various drawbacks, and those having sufficiently satisfactory performance in practical use have not yet been obtained. Not.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a novel compound capable of solving the above-mentioned problems of the prior art, and provides a reversible thermosensitive recording developer containing the same. A new reversible image that can form a color image on a white background, perform color development and decoloration only by differences in heating conditions, has high contrast, and has excellent image storability. It is intended to enable thermal recording.

[0011]

Means for Solving the Problems The present inventors can perform color development and decoloration only by heating, have a high hue contrast between a color-developed part and a decolored part, and have excellent image storability. In order to obtain a reversible thermosensitive recording medium, the inventors of the present invention have conducted intensive studies on a dye-type reversible thermosensitive recording system utilizing the reaction between a dye and a developer.
The present invention has been found, and the present invention has been completed.

The N- (2-naphthylsulfonyl) -N'-phenylurea compound according to the present invention has the following chemical formula (I):

Embedded image [However, in the formula (I), X represents -NHCO-, -NHCOO
Or -NHCOS-, and n represents an integer of 15 to 20].

In the present invention, the compound of the formula (I) may be N- (2-naphthylsulfonyl) -N '-[4-
(n-octadecanoylamino) phenyl] urea, N
-(2-Naphthylsulfonyl) -N '-[4- (n-eicosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-[4- (n-docosanoylamino) phenyl] Urea, N- (2-naphthylsulfonyl) -N '-[4- (n-hexadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-[4- (n-octadecyloxy Carbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-eicosyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-[4- {(N-hexadecylthio) carbonylamino {phenyl] urea, and N
-(2-naphthylsulfonyl) -N '-[4-{(n-
[Octadecylthio) carbonylamino {phenyl] urea.

The developer for reversible thermosensitive recording of the present invention has the following chemical formula (I):

Embedded image (In the formula (I), X represents -NHCO-, -NHCOO-,
Or -NHCOS-, and n represents an integer of 15 to 20. )) And at least one N- (2-naphthylsulfonyl) -N′-phenylurea-based compound represented by the formula:

In the color developer for reversible thermosensitive recording of the present invention, the compound of the formula (I) is selected from the group consisting of N- (2-naphthylsulfonyl) -N '-[4- (n-octadecanoylamino) phenyl] Urea, N- (2-naphthylsulfonyl) -N '-[4- (n-eicosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'
-[4- (n-docosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (
n-hexadecyloxycarbonylamino) phenyl]
Urea, N- (2-naphthylsulfonyl) -N '-[4
-(N-octadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-
[4- (n-Eicosyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '
-[4-{(n-hexadecylthio) carbonylamino} phenyl] urea and N- (2-naphthylsulfonyl) -N '-[4-{(n-octadecylthio) carbonylamino} phenyl] urea Is preferred.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The compound of the formula (I) according to the present invention is useful as a developer for reversible thermosensitive recording, and is preferably a compound of the following formulas (II) to (IV): Is included.

Embedded image

The compound of the formula (I) can be synthesized, for example, by the following reaction 1, 2, or 3.

Embedded image

The compound (A-1) used as a starting material in the above reaction 1 is prepared by, for example, synthesizing an anilide by the reaction of 4-nitroaniline with the corresponding acid chloride of a long-chain aliphatic carboxylic acid, followed by contact. It is obtained by reducing a nitro group to an amino group by a hydrogenation reaction. In addition, the compound (A-
2) is, for example, 4-nitrophenyl isocyanate;
N- (4) obtained by reaction with a long-chain aliphatic alcohol
-Nitrophenyl) carbamic acid ester is obtained by reduction in a catalytic hydrogenation reaction. Further, compound (A-3) used as a raw material in reaction 3
Is obtained, for example, by reducing N- (4-nitrophenyl) thiocarbamic acid S-ester obtained by reaction of 4-nitrophenyl isocyanate with a long-chain aliphatic thiol with tin chloride under acidic conditions. .

In the above Reactions 1 to 3, the compound (B) used as a raw material is obtained by reacting 2-naphthylsulfonamide with potassium carbonate in tetrahydrofuran to form a potassium salt of 2-naphthylsulfonamide,
Then, this is added to the general formula (V):

Embedded image (Wherein, R ₁ represents an alkyl group having 1 to 4 carbon atoms or a phenyl group), thereby reacting with a chloroformate compound represented by the following formula to form a potassium salt of 2-naphthylsulfonyl carbamate, The excess chloroformate compound is distilled off, water is added to dissolve the potassium salt, and the mixture is neutralized with an acid to obtain the following general formula (VI):

Embedded image (Wherein, R ₁ is the same as described above) as a 2-naphthylsulfonyl carbamate.

As the above reaction solvent, compound (B)
(Carbamates) are not particularly limited as long as they do not inhibit the above reaction. Preferred solvents for the above reaction include, for example, dichloromethane, chloroform, carbon tetrachloride, aliphatic halogen compounds such as trichloroethylene, acetonitrile, aliphatic nitriles such as propionitrile, ethyl acetate, propyl acetate, and butyl acetate. Examples thereof include aliphatic esters, aliphatic ethers such as diethyl ether, dibutyl ether and ethylene glycol dimethyl ether, and aliphatic ketones such as 2-butanone and cyclohexanone.

The compound of the present invention is preferably selected from the following compounds. (1) N- (2-naphthylsulfonyl) -N ′-[4- (n-octadecanoylamino) phenyl] urea represented by the formula (VII) (2) N- (2- Naphthylsulfonyl)-
N '-[4- (n-eicosanoylamino) phenyl]
Urea (3) N- (2-naphthylsulfonyl)-of the formula (IX)
N '-[4- (n-docosanoylamino) phenyl] urea (4) N- (2-naphthylsulfonyl)-of the formula (X)
N '-[4- (n-hexadecyloxycarbonylamino) phenyl] urea (5) N- (2-naphthylsulfonyl)-of the formula (XI)
N '-[4- (n-octadecyloxycarbonylamino) phenyl] urea (6) N- (2-naphthylsulfonyl)-of the formula (XII)
N '-[4- (n-Eicosyloxycarbonylamino) phenyl] urea (7) N- (2-naphthylsulfonyl) of the formula (XIII)
-N '-[4-{(n-hexadecylthio) carbonylamino} phenyl] urea and (8) N- (2-naphthylsulfonyl)-of formula (XIV)
N '-[4-{(n-octadecylthio) carbonylamino} phenyl] urea

Embedded image

The reversible thermosensitive recording medium containing the reversible color developing compound of the present invention is prepared by forming a reversible thermosensitive coloring layer on a support. The heat-sensitive recording layer contains a dye precursor and a color developer, and develops color rapidly by heating, and the color development state is rapidly cooled to be stably maintained at room temperature. On the other hand, the color image portion held at room temperature can be erased by heating to a temperature lower than the color development temperature, and the decolored state is maintained even when cooled to room temperature. The mechanism of this color development / decolorization is not clear, but the urea group in the sulfonylurea group in the compound developer of the formula (I) is activated by the sulfonyl group adjacent thereto, so that the basic leuco The dye develops a strong color developing ability and develops color.On the other hand, when the color forming body is heated below the color forming temperature, the naphthyl group and the long-chain alkyl group in the color developer are oriented to crystallize the color developer. It is considered that the dye and the developer are separated and decolorized. Generally, the heating temperature for color development is 80 to 180 ° C.
20 ° C. and lower than the coloring heating temperature. Generally, coloring is performed by a thermal head or the like, which is easy to rapidly cool after heating. Decoloring is performed by maintaining the temperature in a temperature range equal to or lower than the coloring heating temperature, and controls the heating / cooling speed. No need. The temperature holding time at the time of decoloring is preferably 0.1 second or more. The process of recording and erasing the color image will be described with reference to FIG.

In FIG. 1, when the unrecorded recording material in the state A is heated, the color density rapidly increases at the temperature T2 or higher via the state B, and further increases via the state C.
When the coloring reaction is completed, the state reaches the state D, which indicates the highest coloring density. When the state D is rapidly cooled to room temperature, the state F is reached via the state E. State F is a state in which coloring is maintained at room temperature, and the recording of the image is completed. When the recorded image is heated and held in the temperature range T1, the color density gradually decreases, and the state changes to the state A 'via the state G, and the color is completely erased. When this is cooled to room temperature, it reaches state A.
State A is a state where the decolored state is maintained at room temperature,
This completes the erasure of the image. The above color-decoloring reversible cycle can be repeatedly performed.

The compound of the formula (I) of the present invention is contained in a thermosensitive coloring layer of a reversible thermosensitive recording medium together with a dye precursor (leuco dye) and a binder for fixing these components to a support. Further, as an additive for adjusting the color development sensitivity and the color erasing temperature of the reversible thermosensitive recording layer, the melting point is from 50 ° C to 18 ° C.
A thermofusible substance at 0 ° C. (may be a sensitizer used in general thermal paper) can be contained in the reversible thermosensitive recording layer.

The leuco dye used together with the reversible developer compound of the present invention includes triphenylmethane, fluoran and diphenylmethane compounds, and can be selected from conventionally known ones. For example, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, crystal violet lactone, 3- (N-ethyl-N-iso- (Pentylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-
7-anilinofluoran, 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran,
3- (N-ethyl-N-p-toluidino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-dibutylamino-6
-Methyl-7-anilinofluoran, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-diethylamino -7-
(M-trifluoromethylanilino) fluoran, 3-
Diethylamino-6-methyl-7-chlorofluoran,
3-diethylamino-6-methylfluoran and 3-cyclohexylamino-6-chlorofluoran.

Further, 3- (N-ethyl-N-cyclohexyl) -6-methyl-7- (p-chloroanilino)
Fluoran, 3-di (n-pentyl) amino-6-methyl-7-anilinofluoran, 3- [N- (3-ethoxypropyl) -N-ethylamino] -6-methyl-7-
Anilinofluoran, 3- (Nn-hexyl-N-ethylamino) -7- (o-chloroanilino) fluoran, 3- (N-ethyl-N-2-tetrahydrofurfurylamino) -6-methyl- 7-anilinofluoran, 3
-(N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran, 2,2-bis {4-
[6 ′-(N-cyclohexyl-N-methylamino)-
3′-Methylspiro [phthalide-3,9′-xanthen] -2′-ylamino] phenyl} propane and 3
One or more selected from -dibutylamino-7- (o-chloroanilino) fluoran and the like can be used.

Examples of the above-mentioned heat-fusible substances include oxalic acid diesters (JP-A 64-1583) and di (4-methylbenzyl) oxalate (JP-B 5-62597). -Bis (m-tolyloxy) ethane (JP-A-60-56588), diphenylsulfone (JP-A-60-15667) and p-benzylbiphenyl (JP-A-60-82382). These compounds have the ability to enable high-density color development of a reversible thermosensitive recording medium with relatively low applied energy, and also have the ability to promote a decoloring reaction and improve reversibility.

The developer compound of the present invention can be prepared from phenols or organic acids and a sulfonyl (thio) urea aromatic compound having no long-chain alkyl group as long as the desired effect is not impaired. May be used in combination with a conventionally known developer.

The reversible thermosensitive recording layer may further contain waxes and pigments within a range not to impair the effects of the present invention, and usually contains a binder.

As the waxes, for example, known waxes such as paraffin, amide wax and bisimide wax can be used. However, the addition of the zinc salt increases the decoloring density as the color is repeatedly formed and decolored, and the erasing of the color image may be incomplete. Therefore, the content of the zinc salt is determined by the dry weight of the heat-sensitive recording layer. Is preferably 1% by weight or less.

Examples of the pigment include inorganic fine powders such as silica, clay, calcined clay, talc, calcium carbonate, titanium oxide, aluminum hydroxide, barium sulfate and surface-treated calcium carbonate and silica, and urea-based pigments. Examples include organic fine powders such as formalin resin, styrene / methacrylic acid copolymer, and polystyrene resin.

Examples of the binder include polyvinyl alcohols having various molecular weights, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, carboxymethylcellulose, methylcellulose and ethylcellulose;
Sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, polyacrylamide, alginic acid Water-soluble polymer materials such as soda, gelatin, and casein, and polyvinyl acetate, polyurethane, styrene / butadiene copolymer, polyacrylic acid, polyacrylate, vinyl chloride / vinyl acetate copolymer, and polybutyl methacrylate , Ethylene / vinyl acetate copolymer, and styrene /
Latexes such as butadiene / acrylic copolymers can be used.

In order to produce a reversible thermosensitive recording medium, the above-mentioned components are dispersed or dissolved in fine particles, and the resulting mixture is mixed to prepare a coating solution for a thermosensitive coloring layer, which is applied to a sheet-like support. To form a thermosensitive coloring layer. A coating layer such as a protective layer or a printing layer may be formed on the heat-sensitive coloring layer in order to further improve the heat resistance and the repeated durability of coloring and erasing.

The support used in the reversible thermosensitive recording medium of the present invention.
The carrier is paper (acidic) that has been used for conventional thermal recording media.
Paper, neutral paper), and apply pigment, latex, etc.
Coated paper, laminated paper, polyolefin-based
Synthetic paper, polyolefin, polyester made from resin
Glass in addition to plastic films such as
You can choose from plates, conductive rubber sheets, etc.
You. On at least one surface of such a support, the required
Apply a coating solution containing a mixture of components and dry to
A thermal recording medium is manufactured. The amount of coating is the same as when the coating
1 to 15 g / m in the state ^TwoIs preferably 2 to 10 g / m^TwoBut
Particularly preferred.

An apparatus for recording (coloring) and erasing (erasing) an image can be selected from a thermal head, a constant temperature bath, a heating roller, a hot pen, a sheet heating element, a laser beam, an infrared ray, and the like according to the purpose of use. It is possible, but not limited to these.

[0036]

The present invention will be described in detail with reference to the following examples. Unless otherwise specified, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

Synthesis Example 1 Synthesis of methyl (2-naphthylsulfonyl) carbamate In a three-necked flask equipped with a dropping funnel, a thermometer, and a reflux condenser, tetrahydrofuran (3000 m
To l), 2-naphthylsulfonamide (290 g) and potassium carbonate (490 g) were added, and when the mixture was stirred, the reaction system generated heat and 2-naphthylsulfonamide was dissolved to form a potassium salt thereof.

Next, methyl chloroformate (395 g) was added to the reaction mixture, and the mixture was heated under reflux for 48 hours to carry out a reaction. After the completion of the reaction, the temperature in the flask was lowered to 50 ° C. or lower, and tetrahydrofuran and excess methyl chloroformate were distilled off to obtain a potassium salt of methyl (2-naphthylsulfonyl) carbamate. Water (1000 ml) was added thereto to dissolve the potassium salt, and then hydrochloric acid (23) was added thereto.
0 g), and the pH was adjusted to 2 to give methyl (2
342 g of (-naphthylsulfonyl) carbamate precipitated. The yield was 92%.

Synthesis Example 2 N- (2-naphthylsulfonyl) -N '-[4- (n-
Octadecanoylamino) phenyl] urea (VII)
Under a nitrogen atmosphere, p-nitroaniline (138 g) was dissolved in a mixed solution of tetrahydrofuran (200 ml) and pyridine (140 ml) in a three-necked flask equipped with a synthetic dropping funnel, a thermometer, and a reflux condenser. To this solution, octadecanoyl chloride (333 g) was added dropwise from the dropping funnel over 20 minutes with stirring. After the addition was completed, the reaction mixture was stirred for 2 hours. As a result, a solid was formed, which was filtered off, and the filtrate was concentrated under reduced pressure to obtain crystals. The crystals were collected and recrystallized from ethanol to give 4'-nitro-n-octadecaneanilide (364 g). The yield was 90%.

This crystal was treated with tetrahydrofuran (8000
ml), 5% palladium carbon (95 g) was added, and the mixture was vigorously stirred under a hydrogen atmosphere pressurized to 3 atm.
After completion of the reaction, palladium carbon was removed by filtration, and the solvent was removed under reduced pressure to obtain crystals. The crystals were collected and recrystallized from ethanol to give 4'-
Amino-n-octadecaneanilide (300 g) was obtained. The yield was 89%. This was suspended in toluene (6000 ml), and while stirring, methyl (2-naphthylsulfonyl) carbamate (223 g) prepared in Synthesis Example 1 was added, and the reaction mixture was heated under reflux for 5 hours. When the reaction solution was cooled to room temperature, white crystals were precipitated, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the target compound (414 g). The yield was 85%.

The analytical values of the crystals were as follows. Melting point: 192 ° C. Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 22 (br. S, 28
H), 1.53-1.75 (m, 2H), 2.22
(T, 2H), 7.22 (d, 2H), 7.43 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.96 (d, 1H), 8.05 (d, 1H),
8.15 (d, 1H), 8.22 (d, 1H), 8.6
1 (s, 1H), 8.79 (s, 1H), 9.75
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2850,1692,1665,155
2,1520,1451,1405,1160cm ^-1

Synthesis Example 3 N- (2-naphthylsulfonyl) -N '-[4- (n-
Eicosanoylamino) phenyl] urea (VIII)
It could be obtained in a similar manner forming compound (VIII) in Synthesis Example 2. Hereinafter, this synthesis method will be specifically described. In a three-necked flask equipped with a dropping funnel, a thermometer, and a reflux condenser, p-nitroaniline (13
8 g) was dissolved in a mixed solution of tetrahydrofuran (200 ml) and pyridine (140 ml). Under stirring, eicosyl chloride (364 g) was added dropwise from the dropping funnel to the solution in the three-necked flask over 20 minutes. After the addition was completed, the reaction mixture was stirred for 2 hours. Then, a solid was formed. The solid was filtered off, and the filtrate was concentrated under reduced pressure to obtain crystals. The crystals were collected and recrystallized from ethanol to give 4'-nitro-n-eicosananilide (355).
g) was obtained. The yield was 82%.

The crystals were treated with tetrahydrofuran (1000
0 ml), 5% palladium carbon (87 g) was added, and the mixture was vigorously stirred under a hydrogen atmosphere pressurized to 3 atm. After completion of the reaction, palladium carbon was removed by filtration, and the solvent was removed under reduced pressure to obtain crystals. The crystals were collected and recrystallized from ethanol to obtain 4'-
Amino-n-eicosananilide (265 g) was obtained.
The yield was 80%. This is toluene (500
0 ml) and the methyl (2-
(Naphthylsulfonyl) carbamate (183 g) was added and the mixture was refluxed for 5 hours. When the reaction solution was cooled to room temperature, white crystals were deposited, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the desired compound (364 g). The yield was 87%.

The analysis values were as follows. Melting point: 179 ° C. Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 22 (br. S, 32
H), 1.53-1.75 (m, 2H), 2.22
(T, 2H), 7.22 (d, 2H), 7.43 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.96 (d, 1H), 8.05 (d, 1H),
8.15 (d, 1H), 8.22 (d, 1H), 8.6
1 (s, 1H), 8.79 (s, 1H), 9.75
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2855,1690,1660,156
0,1520,1450,1406,1160cm ^-1

Synthesis Example 4 N- (2-naphthylsulfonyl) -N ′-[4- (n-
[Docosanoylamino) phenyl] urea (IX) was obtained in the same manner as in Synthesis Example 2 of Compound (IX). Hereinafter, this synthesis method will be specifically described. P-Nitroaniline (138 g) under a nitrogen atmosphere in a three-necked flask equipped with a dropping funnel, a thermometer, and a reflux condenser.
Was added to tetrohydrofuran (200 ml) and pyridine (140
ml). Under stirring, the docosyl chloride (39) was added to the solution in the three-necked flask from the dropping funnel.
5g) was added dropwise over 20 minutes. After the addition was completed, the reaction mixture was stirred for 2 hours. Then, a solid was formed. The solid was filtered off, and the filtrate was concentrated under reduced pressure to obtain crystals. The crystals were collected and recrystallized from ethanol to obtain 4'-
Nitro-n-docosananilide (405 g) was obtained. The yield was 88%.

The crystals were treated with tetrahydrofuran (1200
0 ml), 5% palladium carbon (92 g) was added, and the mixture was vigorously stirred under a hydrogen atmosphere pressurized to 3 atm. After completion of the reaction, palladium carbon was removed by filtration, and the solvent was removed under reduced pressure to obtain crystals. The crystals were collected and recrystallized from ethanol to obtain 4'-
Amino-n-docosananilide (322 g) was obtained. The yield was 80%. This is toluene (6000
ml) and added with methyl (2-naphthylsulfonyl) carbamate (208 g) of Synthesis Example 1 while stirring.
The mixture was refluxed for 5 hours. When the reaction solution was cooled to room temperature, white crystals were deposited, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the target compound (446 g). The yield was 90%.

The analytical values of the obtained compound were as follows. Melting point: 179 ° C. Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 22 (br. S, 36
H), 1.53-1.75 (m, 2H), 2.22
(T, 2H), 7.19 (d, 2H), 7.43 (d,
2H), 7.65-7.74 (overlapping dd, 1H ×
2), 7.95 (d, 1H), 8.05 (d, 1H),
8.14 (d, 1H), 8.22 (d, 1H), 8.6
1 (s, 1H), 8.79 (s, 1H), 9.73
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2855,1690,1660,156
0,1520,1450,1406,1160cm ^-1

Synthesis Example 5 N- (2-naphthylsulfonyl) -N ′-[4- (n-
Hexadecyloxycarbonylamino) phenyl] uree
A) Synthesis of (X) In a three-necked flask equipped with a dropping funnel, a thermometer, and a reflux condenser, n-hexadecanol (155 g) was dissolved in toluene (1250 ml) under a nitrogen atmosphere. In addition, p-nitrophenyl isocyanate (10
0 g) was added slowly, and the mixture was stirred at room temperature for 10 minutes.
Heated to reflux for minutes. The reaction solution was cooled to room temperature to precipitate crystals. The crystals were separated by filtration and washed with toluene to obtain n-hexadecyl p-nitrophenylcarbamate (240 g). The yield was 97%.

The crystals were treated with tetrahydrofuran (4800
ml), 5% palladium carbon (63 g) was added, and the mixture was vigorously stirred for 2 hours under a hydrogen atmosphere pressurized to 3 atm. After completion of the reaction, palladium carbon is removed by filtration,
When the solvent was further removed under reduced pressure, crystals were obtained.
The crystals were collected, recrystallized from ethanol, and p-
N-hexadecyl aminophenylcarbamate (18
9 g) were obtained. The yield was 85%. This was suspended in toluene (4000 ml) and synthesized with stirring.
Methyl (2-naphthylsulfonyl) carbamate (1
40 g) was added and the mixture was heated under reflux for 5 hours. When the reaction solution was cooled to room temperature, white crystals were deposited, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the desired product (272 g). The yield is 8
9%.

The analytical values of the above crystals were as follows. Melting point: 183 ° C Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 22 (br. S, 26
H), 1.54-1.59 (m, 2H), 4.01
(T, 2H), 7.19 (d, 2H), 7.30 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.96 (d, 1H), 8.06 (d, 1H),
8.15 (d, 1H), 8.22 (d, 1H), 8.6
1 (s, 1H), 8.77 (s, 1H), 9.47
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2850,1695,1552,152
5,1451,1410,1162cm ^-1

Synthesis Example 6 N- (2-naphthylsulfonyl) -N ′-[4- (n-
Octadecyloxycarbonylamino) phenyl] uree
A Synthesis compound (XI) of (XI) was obtained in the same manner as in Synthesis Example 5. The synthesis method is specifically shown below. Dripping funnel,
In a three-necked flask equipped with a thermometer and a reflux condenser, n-octadecanol (173) was placed under a nitrogen atmosphere.
g) was dissolved in toluene (1250 ml). In addition, p
-Nitrophenyl isocyanate (100 g) was slowly added, and the mixture was stirred at room temperature for 10 minutes and then heated and refluxed for 30 minutes. When the reaction solution was cooled to room temperature, crystals precipitated. The crystals were separated by filtration and washed with toluene to give p-
N-octadecyl nitrophenylcarbamate (25
7 g) were obtained. The yield was 97%.

The above crystals were treated with tetrahydrofuran (5000).
ml), 5% palladium carbon (63 g) was added, and the mixture was vigorously stirred for 2 hours under a hydrogen atmosphere pressurized to 3 atm. After completion of the reaction, palladium carbon is removed by filtration,
When the solvent was further removed under reduced pressure, crystals were obtained.
The crystals were collected, recrystallized from ethanol, and p-
N-octadecyl aminophenylcarbamate (20
3 g) was obtained. The yield was 85%. This was suspended in toluene (4000 ml) and synthesized with stirring.
Methyl (2-naphthylsulfonyl) carbamate (1
40 g) was added and the mixture was heated under reflux for 5 hours. When the reaction solution was cooled to room temperature, white crystals were deposited, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the target compound (288 g). The yield was 90%.

The analytical values of the above crystals were as follows. Melting point: 178 ° C Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 22 (br. S, 30
H), 1.53-1.58 (m, 2H), 4.02
(T, 2H), 7.19 (d, 2H), 7.30 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.94 (d, 1H), 8.05 (d, 1H),
8.15 (d, 1H), 8.21 (d, 1H), 8.6
1 (s, 1H), 8.76 (s, 1H), 9.46
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2850,1695,1552,152
5,1451,1410,1162cm ^-1

Synthesis Example 7 N- (2-naphthylsulfonyl) -N ′-[4- (n-
Eicosyloxycarbonylamino) phenyl] urea
A synthetic compound (XII) of (XII) was obtained in the same manner as in Synthesis Example 5. Hereinafter, this synthesis method will be specifically described. Dripping funnel,
In a three-necked flask equipped with a thermometer and a reflux condenser, n-eicosanol (182
g) was dissolved in toluene (1250 ml). In addition, p
-Nitrophenyl isocyanate (100 g) was slowly added, and the mixture was stirred at room temperature for 10 minutes and then heated and refluxed for 30 minutes. When the reaction solution was cooled to room temperature, crystals precipitated. The crystals were separated by filtration and washed with toluene to give p.
-Nitrophenylcarbamic acid-n-eicosyl (27
0 g). The yield was 96%.

The crystals were treated with tetrahydrofuran (5400
ml), 5% palladium carbon (62 g) was added, and the mixture was vigorously stirred under a hydrogen atmosphere pressurized to 3 atm for 2 hours. After completion of the reaction, palladium carbon is removed by filtration,
When the solvent was further removed under reduced pressure, crystals were obtained.
The crystals were collected, recrystallized from ethanol, and p-
Aminophenylcarbamic acid-n-eicosyl (210
g) was obtained. The yield was 83%. This was suspended in toluene (4000 ml), and while stirring, methyl (2-naphthylsulfonyl) carbamate (135 g) of Synthesis Example 1 was added thereto, followed by heating under reflux for 5 hours. When the reaction solution was cooled to room temperature, white crystals were deposited, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the target compound (284 g). The yield was 88%.

The analytical values of the above crystals were as follows. Melting point: 181 ° C Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 21 (br. S, 34
H), 1.55-1.58 (m, 2H), 4.01
(T, 2H), 7.19 (d, 2H), 7.30 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.96 (d, 1H), 8.05 (d, 1H),
8.15 (d, 1H), 8.21 (d, 1H), 8.6
1 (s, 1H), 8.76 (s, 1H), 9.46
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2850,1695,1552,152
5,1451,1410,1162cm ^-1

Synthesis Example 8 N- (2-naphthylsulfonyl) -N ′-[4- (n-
Hexadecylthio) carbonylamino) phenyl] ure
A) Synthesis of (XIII) In a three-necked flask equipped with a dropping funnel, a thermometer, and a reflux condenser, n-hexadecanethiol (165 g) was mixed with acetonitrile (1000 ml) under a nitrogen atmosphere.
Was dissolved. To this, p-nitrophenyl isocyanate (100 g) was slowly added, and pyridine (4
ml) was added dropwise, and the mixture was stirred at room temperature for 10 minutes and then heated and refluxed for 30 minutes. When the reaction solution was cooled to room temperature, crystals were precipitated. The crystals were separated by filtration and washed with acetonitrile to obtain Sn-hexadecyl p-nitrophenylthiocarbamate (250 g). The yield was 97%.

The crystals were suspended in concentrated hydrochloric acid (500 ml) and ethanol (500 ml), and tin chloride dihydrate (55 ml) was added.
0 g) of an ethanol solution (500 ml) is added dropwise. After completion of the dropwise addition, the mixture was heated at 90 ° C. for 2 hours with stirring. After cooling the reaction solution to room temperature, the hydrochloride was collected by filtration, suspended in water (1000 ml), and neutralized with triethylamine. This was filtered off with suction and recrystallized from ethanol to obtain Sn-hexadecyl p-aminophenylcarbamate (200 g). The yield was 86%. This is toluene (4
2,000 ml), and with stirring, methyl (2-naphthylsulfonyl) carbamate of Synthesis Example 1 (142 g).
Was added and heated under reflux for 5 hours. When the reaction solution was cooled to room temperature, white crystals were precipitated, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the target compound (287 g). The yield was 90%.

The analytical values of the above crystals were as follows. Melting point: 190 ° C. Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 25 (br. S, 26
H), 1.49-1.54 (m, 2H), 2.82
(T, 2H), 7.22 (d, 2H), 7.35 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.96 (d, 1H), 8.05 (d, 1H),
8.15 (d, 1H), 8.22 (d, 1H), 8.6
2 (s, 1H), 8.87 (s, 1H), 10.15
(S, 1H)

Result of IR measurement (KBr tablet method): 330
0,2920,2850,1692,1650,155
2,1520,1451,1405,1160cm ^-1

Synthesis Example 9 N- (2-naphthylsulfonyl) -N ′-[4- (n-
Octadecylthio) carbonylamino) phenyl] uree
A Synthesis compound (XIV) of (XIV) was also obtained in the same manner as in Synthesis Example 8. Hereinafter, this synthesis method will be specifically described. Dripping funnel,
In a three-necked flask equipped with a thermometer and a reflux condenser, n-octadecanethiol (1
83 g) was dissolved in acetonitrile (1000 ml).
To this solution was added p-nitrophenyl isocyanate (10
0 g) was added slowly, and pyridine (4 ml) was further added dropwise. After stirring at room temperature for 10 minutes, the mixture was heated under reflux for 30 minutes.
When the reaction solution was cooled to room temperature, crystals were precipitated. The crystals were separated by filtration and washed with acetonitrile to give p-
Sn-octadecyl nitrophenylthiocarbamate (272 g) was obtained. The yield was 99%.

The crystals were suspended in concentrated hydrochloric acid (500 ml) and ethanol (500 ml), and a solution of tin chloride dihydrate (550 g) in ethanol (500 ml) was added dropwise. After completion of the dropwise addition, the mixture was heated at 90 ° C. for 2 hours with stirring. After the reaction solution was cooled to room temperature, the hydrochloride was filtered off and water (100
0 ml) and neutralized with triethylamine. This was filtered off with suction and recrystallized from ethanol to give Sn-octadecyl p-aminophenylcarbamate (23
1 g). The yield was 91%. This was suspended in toluene (4000 ml) and synthesized with stirring.
Methyl (2-naphthylsulfonyl) carbamate (1
53 g) was added and the mixture was heated under reflux for 5 hours. When the reaction solution was cooled to room temperature, white crystals were precipitated, and this was filtered under reduced pressure. The crystals were washed with acetonitrile and dried under reduced pressure to obtain the desired compound (320 g).
The yield was 89%.

The analytical values of the above crystals were as follows. Melting point: 193 ° C. Results of ¹ H-NMR measurement (in deuterated methyl sulfoxide)
(Numbers ppm) δ = 0. 84 ( t, 3H), 1. 21 (br. S, 30
H), 1.49-1.54 (m, 2H), 2.83
(T, 2H), 7.22 (d, 2H), 7.35 (d,
2H), 7.67-7.75 (overlapping dd, 1H ×
2), 7.96 (d, 1H), 8.05 (d, 1H),
8.15 (d, 1H), 8.22 (d, 1H), 8.6
1 (s, 1H), 8.88 (s, 1H), 10.15
(S, 1H)

The result of IR measurement (KBr tablet method): 330
0,2920,2850,1692,1650,155
2,1520,1451,1405,1160cm ^-1

Production Example 1 of Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced by the following operation. (1) using a sand grinder Dispersion Preparation Ingredients Amount of A (parts) 3-dibutylamino-6-methyl-7-20 anilinofluoran polyvinyl alcohol 10% solution 10 Water 70 The composition, average particle size Is 1
It was pulverized until it became not more than μm.

[0072] (2) Preparation Ingredients Amount of Dispersion B (parts) N-(2-naphthylsulfonyl) -N '- [4- (n- octadecanoylamino)-phenyl] urea (Compound VII) 20 polyvinyl Alcohol 10% liquid 10 Water 70 The above composition was sand-ground using an average particle size of 1
It was pulverized until it became not more than μm. (3) Preparation Ingredients Amount of Dispersion C (parts) of oxalic acid - using a sand grinder di -p- methylbenzyl ester 20 polyvinyl alcohol 10% solution 10 Water 70 The composition, average particle size of 1
It was pulverized until it became not more than μm.

(4) Formation of Reversible Thermosensitive Recording Layer In 75 parts of solution A, 150 parts of solution B and 75 parts of solution C,
30 parts of calcined clay, 2 parts of a 25% paraffin wax emulsion, and 100 parts of a 10% aqueous polyvinyl alcohol solution were mixed and stirred to prepare a coating solution. This coating solution was applied on one side of a support made of a polyester film having a thickness of 75 μm so that the coated amount after drying was 5.0 g / m ^2, and dried to form a reversible thermosensitive recording layer. . (5) Super calender treatment The heat-sensitive recording sheet obtained as described above was treated with a super calender, and the surface smoothness of the heat-sensitive coloring layer was adjusted to 3000 to 5000 seconds to obtain a reversible heat-sensitive recording material. .

(6) Color Reproducibility, Decolorability Test The reversible thermosensitive recording medium obtained as described above was subjected to a printing voltage of 2 using a thermal coloration tester THPMD manufactured by Okura Electric.
Printing was performed under the conditions of 1.7 v and a print pulse of 1.0 ms. The print color density was measured with a Macbeth reflection densitometer RD-914. Furthermore, after heating this color-developed sample under the conditions of a heating temperature of 100 ° C., a pressure of 1 kg / cm ² , and a heating time of 1 second using a thermal gradient tester manufactured by Toyo Seiki, the decolorization density was measured using a Macbeth reflection densitometer RD-914. Was measured. Table 1 shows the test results. (7) Storage test The density of an image immediately after printing and color development was measured in the same manner as in the color development test described in the above (6), and the obtained color sample was subjected to 40 tests.
The color density after standing for 14 days under the condition of ° C. was measured in the same manner. Image preservation ratio at this time: (color density after standing at 40 ° C. for 14 days / color density immediately after printing) × 100 (%)
The storage stability of the image portion was evaluated by the following. Table 1 shows the test results.

Example 2 of Production of Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N '-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-[4- (n-eicosanoylamino) phenyl] Urea (compound VIII) was used. Table 1 shows the test results.

Example 3 of Production of a Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of a reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N '-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-[4- (n-docosanoylamino) phenyl] urea (Compound IX) was used. Table 1 shows the test results.

Example 4 of Production of a Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of a reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N '-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-[4- (n-hexadecyloxycarbonylamino) phenyl ] Urea (Compound X)
Was used. Table 1 shows the test results.

Example 5 of Production of Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N '-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-[4- (n-octadecyloxycarbonylamino) phenyl] Urea (compound XI)
Was used. Table 1 shows the test results.

Example 6 of Production of Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N '-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-[4- (n-eicosyloxycarbonylamino) phenyl ] Urea (Compound XII)
Was used. Table 1 shows the test results.

Example 7 of Production of Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N '-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-[4-{(n-hexadecylthio) carbonylamino} phenyl ] Urea (Compound X
III) was used. Table 1 shows the test results.

Example 8 of Production of Reversible Thermosensitive Recording Sheet A reversible thermosensitive recording sheet was produced and tested in the same manner as in Production Example 1 of reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl)-
Instead of N ′-[4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N ′-[4-{(n-octadecylthio) carbonylamino} Phenyl] urea (compound X
IV) was used. Table 1 shows the test results.

Examples of production of reversible thermosensitive recording sheets 1 to 8
In each of the cases, the repetition of the coloring and decoloring of the image was smoothly performed. Therefore, it was confirmed that the reversible thermosensitive recording medium using the developer compound of the present invention can withstand repeated use.

Comparative Example 1 A reversible thermosensitive recording sheet was prepared and tested in the same manner as in Production Example 1 of the reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl) -N'-
Instead of [4- (n-octadecanoylamino) phenyl] urea (compound VII), a stearylamine salt of gallic acid was used. Table 1 shows the test results.

Comparative Example 2 A reversible thermosensitive recording sheet was prepared and tested in the same manner as in Production Example 1 of the reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl) -N'-
Ascorbic acid was used instead of [4- (n-octadecanoylamino) phenyl] urea (compound VII). Table 1 shows the test results.

Comparative Example 3 A reversible thermosensitive recording sheet was prepared and tested in the same manner as in Production Example 1 of the reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl) -N'-
Instead of [4- (n-octadecanoylamino) phenyl] urea (compound VII), 4′-hydroxy-n-
Octadecaneanilide was used. Table 1 shows the test results.

Comparative Example 4 A reversible thermosensitive recording sheet was prepared and tested in the same manner as in Production Example 1 of the reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl) -N'-
Instead of [4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (p-toluenesulfonyl) -N ′-[4- (n-octadecanoylamino) phenyl] urea is used. Was. Table 1 shows the test results.

Comparative Example 5 A reversible thermosensitive recording sheet was prepared and tested in the same manner as in Production Example 1 of the reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl) -N'-
Instead of [4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (p-toluenesulfonyl) -N ′-[4- (n-hexadecyloxycarbonylamino) phenyl] urea was used. Using. Table 1 shows the test results.

Comparative Example 6 A reversible thermosensitive recording sheet was prepared and tested in the same manner as in Production Example 1 of the reversible thermosensitive recording sheet. However, when preparing the dispersion B, N- (2-naphthylsulfonyl) -N'-
Instead of [4- (n-octadecanoylamino) phenyl] urea (compound VII), N- (p-toluenesulfonyl) -N ′-[4-{(n-octadecylthio) carbonylamino} phenyl] urea Was used. Table 1 shows the test results.

[0089]

[Table 1]

As is clear from Synthesis Examples 2 to 9, N- (2-naphthylsulfonyl) -N ′-[4-
(n-octadecanoylamino) phenyl] urea (compound VII), N- (2-naphthylsulfonyl) -N'-
[4- (n-eicosanoylamino) phenyl] urea (compound VIII), N- (2-naphthylsulfonyl)-
N '-[4- (n-docosanoylamino) phenyl] urea (compound IX), N- (2-naphthylsulfonyl)-
N '-[4- (n-hexadecyloxycarbonylamino) phenyl] urea (compound X), N- (2-naphthylsulfonyl) -N'-[4- (n-octadecyloxycarbonylamino) phenyl] urea ( Compound X
I), N- (2-naphthylsulfonyl) -N '-[4-
(n-Eicosyloxycarbonylamino) phenyl]
Urea (compound XII), N- (2-naphthylsulfonyl) -N '-[4-{(n-hexadecylthio) carbonylamino} phenyl] urea (compound XIII), and N- (2-naphthylsulfonyl) -N' − [4-
{(N-octadecylthio) carbonylamino} phenyl] urea (Compound XIV) is a well-identified new compound. Further, as is clear from Table 1, by using the compound of the present invention as a developer of a reversible thermosensitive recording medium, it is possible to obtain a higher color density and a lower decoloring density than the conventional dye-type reversible thermosensitive recording medium. Can be. That is, it is possible to obtain a reversible thermosensitive recording medium having extremely high contrast between the color-developed portion and the decolored portion. Further, the color image obtained from the obtained reversible thermosensitive recording medium shows an image preservation ratio of 85% or more even after storage for 14 days in an atmosphere at 40 ° C., indicating that the reversible thermosensitive recording medium using the compound of the present invention as a color developer It was confirmed that the thermal recording medium had extremely high preservability.

[0091]

The compound of the formula (I) of the present invention, especially N-
(2-Naphthylsulfonyl) -N '-[4- (n-octadecanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-[4- (n-eicosanoylamino) phenyl] Urea, N- (2-naphthylsulfonyl) -N '-[4- (n-docosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl)-
N '-[4- (n-hexadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-[4- (n-octadecyloxycarbonylamino) phenyl] urea, N- (2 -Naphthylsulfonyl) -N '-[4- (n-eicosyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N'-[4-{(n-hexadecylthio)
Carbonylamino {phenyl] urea and N- (2-naphthylsulfonyl) -N ′-[4-{(n-octadecylthio) carbonylamino} phenyl] urea are novel compounds and are developers for reversible thermosensitive recording. Is useful as That is, the reversible thermosensitive recording medium using the compound of the present invention as a color developer has a higher contrast between a color-developed portion and a decolored portion than those using a conventional color developer, and has excellent storage stability of a color-formed image. It is of very high practical value.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the temperature and the color density in a cycle of color development and decoloration of a thermosensitive recording medium containing a developer for reversible thermosensitive recording of the present invention.

Claims (4)

[Claims] 1. The following chemical formula (Ι): [However, in the formula (I), X represents -NHCO-, -NHCO
N- (2-naphthylsulfonyl) -N'-phenylurea-based compound represented by O- or -NHCOS-, and n represents an integer of 15 to 20]. 2. The compound of the formula (I), wherein N- (2-naphthylsulfonyl) -N ′-[4- (n-
Octadecanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Eicosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Docosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Hexadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Octadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Eicosyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4-{(n
-Hexadecylthio) carbonylamino {phenyl] urea, and N- (2-naphthylsulfonyl) -N '-[4-{(n
The compound according to claim 1, which is selected from [octadecylthio) carbonylamino {phenyl] urea. 3. The following chemical formula (I): (Wherein, in the formula (I), X represents -NHCO-, -NHC
OO- or -NHCOS-, wherein n is 15 to 20
Represents an integer. And N- (2-naphthylsulfonyl) -N'-phenylurea-based compound represented by the formula (1). 4. The compound of the formula (I), wherein N- (2-naphthylsulfonyl) -N ′-[4- (n-
Octadecanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Eicosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Docosanoylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Hexadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Octadecyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4- (n-
Eicosyloxycarbonylamino) phenyl] urea, N- (2-naphthylsulfonyl) -N '-[4-{(n
-Hexadecylthio) carbonylamino {phenyl] urea, and N- (2-naphthylsulfonyl) -N '-[4-{(n
The developer for reversible thermosensitive recording according to claim 3, which is selected from [octadecylthio) carbonylamino {phenyl] urea.